U.S. patent number 6,141,968 [Application Number 08/960,331] was granted by the patent office on 2000-11-07 for fuel nozzle for gas turbine engine with slotted fuel conduits and cover.
This patent grant is currently assigned to Pratt & Whitney Canada Corp.. Invention is credited to Roger Jonathan Gates, Pierre Juteau, Richard Alan Kostka, Giovanni Mario Mulas, Lev Alexander Prociw, Harris Shafique, Bastien Ste. Marie.
United States Patent |
6,141,968 |
Gates , et al. |
November 7, 2000 |
Fuel nozzle for gas turbine engine with slotted fuel conduits and
cover
Abstract
A stem member for a gas turbine fuel nozzle includes inlet and
outlet ends which are respectively adapted to be connected to a
fuel adapter which is coupled to a fuel injector and a tip assembly
having at least one spray orifice for atomizing fuel into a
combustion chamber. The stem member further includes at least one
slot which is sealed throughout the length thereof by a slot cover
so as to define at least one fuel conduit for directing fuel flow
from the inlet end to the outlet end of the stem member. An outer
shield can be disposed outwardly of the stem member to protect and
limit the transfer of heat from the surroundings to the stem
member.
Inventors: |
Gates; Roger Jonathan
(Montreal, CA), Juteau; Pierre (St. Jean Baptiste,
CA), Mulas; Giovanni Mario (Montreal, CA),
Shafique; Harris (Longueuil, CA), Ste. Marie;
Bastien (Varennes, CA), Prociw; Lev Alexander
(Elmira, CA), Kostka; Richard Alan (Maple,
CA) |
Assignee: |
Pratt & Whitney Canada
Corp. (Longueuil, CA)
|
Family
ID: |
25503056 |
Appl.
No.: |
08/960,331 |
Filed: |
October 29, 1997 |
Current U.S.
Class: |
60/740; 239/423;
60/742; 60/746; 60/796 |
Current CPC
Class: |
F02C
7/222 (20130101); F23R 3/283 (20130101) |
Current International
Class: |
F02C
7/22 (20060101); F23R 3/28 (20060101); F02C
003/00 () |
Field of
Search: |
;6/39.31,261,267,740,742,746,739 ;239/423,424 ;138/115,117 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Kim; Ted
Attorney, Agent or Firm: Astle; Jeffrey W.
Claims
We claim:
1. In a gas turbine fuel nozzle comprising a stem member having
inlet and outlet ends respectively coupled in flow communication
with a fuel adaptor and a spray tip assembly, the improvement in
combination therewith comprising a solid one piece of material
forming said stem member and extending continuously from said fuel
adaptor to said spray tip assembly, slot means defined in a
peripheral surface of said solid one piece of material and
extending along a portion of a length thereof comprised between the
inlet and outlet ends, said slot means being sealed throughout the
length thereof by cover means so as to define at least one fuel
conduit for directing fuel flow from said fuel adaptor to said
spray tip assembly which are respectively mounted to said inlet and
outlet ends defined at opposed end portions of said solid one piece
of material.
2. A combination as defined in claim 1, wherein said inlet and
outlet ends are each provided with primary and secondary conduits,
and wherein said slot means function as a primary and a secondary
fuel conduit, said primary and secondary fuel conduits being
respectively connected in flow relationship with said primary
conduits and said secondary conduits, whereby a primary and a
secondary fuel flow can pass through said stem member.
3. A combination as defined in claim 2, wherein said primary and
secondary fuel conduits are disposed on the same side of said stem
member and wherein said primary and secondary conduits include a
single cover means.
4. A combination as defined in claim 3, wherein there is provided a
cutout portion in said stem member for lightening purposes.
5. A combination as defined in claim 2, wherein said primary and
said secondary fuel conduits are disposed on opposite sides of said
stem member and wherein said primary and secondary fuel conduits
each includes a cover means.
6. A combination as defined in claim 5, wherein there is provided a
plurality of holes for lightening purposes, said holes extending in
a plane which is perpendicular to said primary and secondary fuel
conduits.
7. A combination as defined in claim 1, wherein an outer shield
means surrounds said stem member for providing thermal insulation
to said stem member.
8. A combination as defined in claim 7, wherein said shield means
is a cylindrical sleeve.
9. A combination as defined in claim 8, wherein said cylindrical
sleeve is supported at opposite ends thereof by said stem member
and is spaced apart therefrom between said opposite ends, said
cylindrical sleeve being brazed to said stem member.
10. In a gas turbine fuel nozzle comprising a fuel adaptor
interconnected in flow communication with a spray tip assembly via
a stem member, the improvement in combination therewith comprising
a one-piece body defining opposed inlet and outlet ends to which
said fuel adaptor and said spray tip assembly are adapted to be
respectively mounted, slot means defined in a peripheral surface of
said one-piece body along a portion of a length thereof extending
between said inlet and outlet ends, and cover means cooperating
with said slot means to define at least one fuel conduit having
opposed ends respectively coupled in flow communication with said
fuel adaptor and said spray tip assembly, whereby at least one fuel
flow can pass from said fuel adaptor through said stem member to
said spray tip assembly.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel nozzle for gas turbines
engines and, more particularly, to a fuel nozzle stem through which
distinct fuel conduits can be defined.
2. Description of the Prior Art
Fuel nozzles for gas turbine engines are well known in the prior
art. Such conventional fuel nozzles are used to supply fuel to a
combustion chamber which is provided for igniting the fuel mixture,
thereby producing the energy which is used to power the engine.
Generally, the combustion chamber includes a plurality of fuel
nozzles to thus ensure a proper distribution of the fuel mixture
within the combustion chamber.
Conventional fuel nozzles include an inlet housing which is coupled
to a fuel injector, a stem portion which defines dual fuel passages
and at least one tip assembly of the nozzle for spraying or
atomizing fuel into the combustion chamber. More particularly, the
stem portion of such fuel nozzles consists of a primary tube and a
secondary tube which are disposed within an outer tube which is
adapted to provide structural support and thermal insulation to the
tubing assembly. Indeed, the outer tube is exposed to hot
compressor discharge air and thus some spacers are required to
protect the inner tubes, i.e., the primary and secondary tubes,
from contact with the hot outer tube.
Typically, the primary tube and the secondary tube are
concentrically disposed within the outer tube so as to define two
distinct conduits for directing primary and secondary fuel flows
respectively. More particularly, the primary fuel is conveyed
through a conduit of circular cross-section defined by the primary
tube while the secondary fuel is delivered through the annular
space defined between the primary and the secondary tube.
According to another configuration of the above fuel nozzle, the
primary and the secondary tubes are not concentrically disposed
within the outer tube, and thus the secondary fuel flows through
the circular conduit of the secondary tube instead of passing
through the annular space which is comprised between the primary
and secondary tubes of the previous concentric structure. U.S. Pat.
No. 4,735,044, issued on Apr. 5, 1988 to Richey et al, and U.S.
Pat. Nos. 5,423,178 and 5,570,580, respectively issued on Jun. 13,
1995 and Nov. 5, 1996 to Mains, disclose such a dual stem for a gas
turbine fuel nozzle.
U.S. Pat. No. 3,684,186, issued on Aug. 15, 1972 to Helmrich, and
U.S. Pat. No. 4,609,150, issued on Sep. 2, 1986 to Pane, Jr. et al,
teach having fuel and air passages which extend through a single
element. More particularly, U.S. Pat. No. 3,684,186 discloses an
aerating fuel nozzle which comprises a primary fuel passage, a
secondary fuel passage and a plurality of circumferentially spaced
air passages, all these passages being drilled through the main
support structure of the fuel nozzle or defined by the space that
exists between some adjacent components of the aerating fuel
nozzle. U.S. Pat. No. 4,609,150 discloses a fuel nozzle which is
cast into two distinct portions, one being the main support
structure and the other being the nozzle head. More particularly, a
fuel passage and an air passage are cast into the main support
structure, and the nozzle head is provided with air swirler vanes,
a frusto-conical air passage and a fuel swirl orifice plate. The
head portion is welded to the end of the nozzle support portion so
as to form an integral fuel nozzle.
SUMMARY OF THE INVENTION
It is, therefore, an aim of the present invention to provide an
improved nozzle stem member which is adapted to convey fuel from a
fuel injector to a combustion chamber.
It is also an aim of the present invention to provide such a stem
member which is relatively simple and economical to
manufacture.
A construction in accordance with the present invention comprises a
stem member for a gas turbine fuel nozzle having inlet and outlet
ends. The stem member includes a solid piece of material. Slot
means are defined in the periphery 30 of the solid piece and extend
between the inlet and outlet ends of the stem member. The slot
means are sealed throughout the length thereof by cover means so as
to define at least one fuel conduit for directing fuel flow from
the inlet end to the outlet end.
Typically, the inlet end is adapted to be coupled to a fuel adapter
which is connected to a fuel injector for supplying fuel through
the stem member. The outlet end of the stem is adapted to be
coupled to a spray tip assembly which is provided with at least one
spray orifice through which fuel can be atomized for combustion
purposes.
Also typically, an outer shield means surrounds said stem member
for providing thermal insulation to said stem member. More
specifically, the shield means is a cylindrical sleeve which is
supported at opposite ends thereof by the stem member. The
cylindrical sleeve is spaced apart from the stem member between the
opposite ends thereof.
In a more specific construction in accordance with the present
invention, the inlet and outlet ends of the stem member are each
provided with primary and secondary conduits. The slot means
function as a primary and a secondary fuel conduit which are
respectively connected in flow relationship with the primary
conduits and the secondary conduits, whereby a primary and a
secondary fuel flow can pass through the stem member. The primary
and secondary fuel conduits can be disposed on the same side of the
stem member and include a single cover means. Alternatively, the
primary and secondary fuel conduits can be disposed on opposite
sides of the stem member and can include a distinct cover means for
each such fuel conduits. According to another general aspect of the
present invention, there is provided a stem member for a gas
turbine fuel nozzle, including a body having a peripheral surface,
slot means machined in said peripheral surface, cover means
cooperating with said slot means to define at least one fuel
conduit having inlet and outlet ends, whereby at least one fuel
flow can pass through said stem member.
A method in accordance with the present invention of forming a stem
member for a gas turbine fuel nozzle comprises the steps of first
preparing a solid piece of material. Second, the opposite ends of
the solid piece of material are bored for defining inlet and outlet
ends. Third, slot means are defined along the portion of the length
of the solid piece of material which extends between the inlet and
outlet ends. Finally, the slot means are sealed with cover means so
as to define at least one fuel conduit to convey a fuel flow from
the inlet end to the outlet end of the stem member .
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the nature of the invention,
reference will now be made to the accompanying drawings, showing by
way of illustration a preferred embodiment thereof, and in
which:
FIG. 1 is an exploded perspective view of a stem member of a gas
turbine fuel nozzle according to the present invention, with the
peripheral elements thereof being shown in dotted lines;
FIG. 2 is a cross-sectional view taken along the line 2--2 of FIG.
1, showing the slots which form the primary and secondary fuel
conduits with the respective primary and secondary outlet conduits
thereof;
FIG. 3 is a perspective view of the stem member of a gas turbine
fuel nozzle according to a second preferred embodiment of the
present invention;
FIG. 4 is a plan view of the outlet end of the stem member shown in
FIG. 3;
FIG. 5 is a side view of the stem member of FIG. 3, showing the
slot which defines the secondary fuel conduit with the secondary
inlet and outlet conduits thereof and the outer shield being
illustrated in dotted lines;
FIG. 6 is a side view of the stem member of FIG. 3, showing the
slot which defines the primary fuel conduit with the inlet and
outlet conduits thereof;
FIG. 7 is a top plan view of the stem member of FIG. 3; and
FIG. 8 is a cross-sectional view taken along the line 8--8 of FIG.
7 of the stem member of FIG. 3, showing the two slots which form
the primary and secondary fuel conduits.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now referring to the drawings, and in particular to FIG. 1, a fuel
nozzle of a gas turbine engine embodying the elements of the
present invention and generally designated by numeral 10 will be
described. The fuel nozzle 10 includes a stem member 12 which is
adapted to be coupled at the inlet end 14 thereof to a fuel
manifold adapter 16 and at the outlet end 18 thereof to a spray tip
assembly 20. Accordingly, the spray tip assembly 20 is coupled
through the stem member 12 to the fuel manifold adapter 16 which is
connected to a fuel injector (not shown). Therefore, the fuel
supplied by the fuel injector will be atomized by the spray tip
assembly 20 for ignition in a combustion chamber (not shown), as is
well known in the art.
More particularly, the stem member 12 includes primary and
secondary fuel conduits 22 and 24 for respectively directing a
primary and a secondary fuel flow from the inlet end 14 to the
outlet end 18 of the stem member 12. The primary and secondary fuel
conduits 22 and 24 are formed by two distinct slots 26 and 28 which
are defined on the same side of the stem member 12 and closed by a
cover 30 welded thereon. More specifically, the cover 30 is fitted
within a rectangular cutout portion 31 along which the slots 26 and
28 extend in a collinear fashion. It is noted that the cover 30 and
the cutout portion 31 have basically the same length and width.
This thus prevents longitudinal displacement of the cover 30 and
also facilitates the positioning of the same with respect to the
slots 26 and 28. The primary and secondary fuel conduits 22 and 24
are respectively fed through primary and secondary inlet conduits
(not shown) which are defined at the inlet end 14 of the stem
member 12. As best seen in FIG. 2, primary and secondary outlet
conduits 32 and 34 are provided at the outlet end 18 of the stem
member 12 for receiving the primary and the secondary fuel flow
which are conveyed by the primary and secondary fuel conduits 22
and 24, respectively. Therefore, this configuration of the stem
member 12 allows for simultaneously or subsequently directing two
distinct fuel flows from an inlet end 14 to an outlet end 18.
A portion of the inlet end 14 of the stem member 12 is adapted to
be inserted into a receiving opening (not shown) defined in the
bottom portion of the fuel manifold adapter 16. The fuel manifold
adapter 16 is provided with primary and secondary fuel outlets (not
shown) which can be connected in flow relationship with the primary
and secondary inlet conduits (not shown) of the stem member 12.
Therefore, once the inlet end 14 of the stem member 12 has been
introduced into the receiving opening of the fuel manifold adapter
16 such that the primary and secondary inlet conduits (not shown)
of the stem member 12 are properly aligned with the primary and
secondary fuel outlets of the fuel manifold adapter 16, the stem
member 12 is secured to the fuel manifold adapter 16 by way of
welding, brazing or the like. As seen in FIG. 1, the fuel manifold
adapter 16 is provided with a flange 36 for mounting the fuel
nozzle 10 to the combustion chamber or other casing of the gas
turbine engine, as is known in the art.
The outlet end 18 of the stem member 12 is coupled to a spray tip
assembly 20 which includes a primary distributor 38, a primary cone
40, and a primary shield 42 which are coupled to receive the
primary flow through the primary inlet conduit (not shown), the
primary fuel conduit 22, and the primary outlet conduits 32. The
spray tip assembly 20 further includes a secondary fuel swirler 44
to receive the secondary fuel flow through the secondary inlet
conduit (not shown), the secondary fuel conduits 24, and the
secondary outlet conduits 34. Finally, the spray tip assembly 20
includes an outer air swirler 46 which is provided with a plurality
of circumferentially spaced air passages 48 which are adapted to
convey air flow for blending with the primary and secondary fuel
sprays issuing from the primary and secondary spray orifices of the
spray tip assembly 20, respectively. The primary distributor 38 and
the primary cone 40 are brazed into the receiving opening (not
shown) defined at the outlet end 18 of the stem member 12. For its
part, the primary shield 42 is brazed to the primary cone 40. The
secondary fuel swirler 44 is brazed to the interior surface of the
cylindrical portion 50 of the outer air swirler 46. The outlet end
18 of the stem member 12 is brazed to the interior surface of the
cylindrical portion 50 of the outer air swirler 46 so as to form an
integral assembly.
As seen from FIG. 1, a second cutout portion 52 is defined along a
portion of the length of the stem member 12 for lightening
purposes. An outer shield 54 has, at opposite ends thereof, inside
diameters which generally correspond to the outside diameters of
the portions which are adjacent to the cutout portions 31 and 52 of
the stem member 12. Therefore, the outer shield 54 can be mounted
to the stem member 12 to protect the same from the severe
surrounding conditions which prevail in a gas turbine engine. More
specifically, the outer shield 54 can be brazed to the stem member
12.
According to the construction of the stem member 12, it is noted
that the primary and secondary inlet conduits (not shown), the
slots 26 and 28, and the primary and secondary outlet conduits 32
and 34, are all obtained by machining operations. Therefore,
primary and secondary fuel conduits 22 and 24 are provided by
machining a single solid piece of material. Typically, the stem
member 12 is formed of materials, such as stainless steel.
Referring now to FIGS. 3 to 8, another form of the stem member of
the present invention is generally designated by the numeral 200.
It is seen from FIGS. 3 to 8 that the slots 202 and 204 are defined
on opposite sides of the stem member 200. As illustrated in FIG. 8,
both slots 202 and 204 are basically U-shaped. However, slot 204
has a larger cross-sectional area which is adapted to receive a
secondary fuel flow. It is also observed from FIG. 3 that a
distinct cover 206 is provided for each slot 202 and 204. Moreover,
a series of holes 207 is defined in the central portion of the stem
member 200, i.e., between the two slots 202 and 204, for lightening
purposes. These holes 207 extend transversally with respect to the
longitudinal axis of the stem member 200.
As best seen from FIGS. 3 and 4, the outlet end 208 of the stem
member 200 is provided with a receiving opening 210 into which the
primary portion, namely, the primary distributor, the primary cone,
and the primary shield, of a spray tip assembly, such as the one
described hereinbefore, can be mounted. It is also seen from FIG. 4
that the outlet end 208 of the stem member 200 is provided with
primary and secondary outlet conduits 212 and 214 which are
respectively connected in flow relationship with associated slot
202 and 204 thereof for supplying a primary and a secondary fuel
flow to a spray tip assembly (not shown) having primary and
secondary spray orifices. The outlet end 208 and the inlet end 216
of the stem member 200 are nonlinear as best seen in FIGS. 5 and 6.
Indeed, the outlet end 208 is machined so as to define an angle
with the longitudinal axis of the stem member 200.
Referring now to FIGS. 6 and 7, the inlet end 216 of the stem
member 200 is provided with a central opening 218 from which
extends a primary inlet conduit 220. The slot 202 is thus
respectively connected in flow relationship at opposite ends
thereof to primary inlet and outlet conduits 212 and 220, as best
seen in FIG. 7. It is also easily seen that the slot 204 is
respectively connected in flow relationship at opposite ends
thereof with secondary inlet and outlet conduits 214 and 222. This
is best seen in FIG. 5 as well as in FIG. 7.
As for the first embodiment of the present invention, an outer
shield 224 is provided for protecting the stem member 200, as best
seen in FIGS. 3 and 5.
* * * * *